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Composiciones isotópicas de la materia cometaria devuelta por el polvo estelar
Kevin D McKeegan1, Jerome Aléon, John Bradley
1Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095-1567, USA. mckeegan@ess.ucla.edu
Science (New York, N.Y.)
|December 16, 2006
Resumen
El cometa 81P/Wild 2 contiene materiales tanto del interior como del exterior del sistema solar, no solo materia presolare prístina. El análisis isotópico revela una mezcla de orígenes, desafiando la idea de un cometa puramente primordial.
Área de la Ciencia:
- Análisis del polvo cósmico Análisis del polvo cósmico
- Ciencia de los Cometas Ciencia de los Cometas
- La geoquímica de los isótopos es la geoquímica de los isótopos.
Sus antecedentes:
- Los cometas son restos del sistema solar primitivo, ofreciendo pistas sobre su formación.
- El cometa 81P/Wild 2 ha sido estudiado por su composición única, potencialmente preservando materiales primordiales.
Objetivo del estudio:
- Para investigar la composición isotópica de los fragmentos de partículas del cometa 81P/Wild 2.
- Para determinar el origen de los materiales dentro del cometa y evaluar su naturaleza prístina.
Principales métodos:
- Análisis de las composiciones isotópicas de hidrógeno, carbono, nitrógeno y oxígeno en fragmentos de cometas.
- Examen de las firmas mineralógicas e isotópicas de los granos individuales.
Principales resultados:
- Se observó heterogeneidad isotópica, pero las anomalías extremas fueron raras, lo que sugiere un material presolar limitado.
- Los isótopos de nitrógeno y neón no terrestres indican la presencia de materia orgánica y volátil autóctona.
- La mayoría de los silicatos y óxidos mostraron orígenes isotópicos del sistema solar, con un grano refractario exhibiendo enriquecimiento con (16) O, indicativo de la formación del sistema solar interior.
Conclusiones:
- El cometa 81P/Wild 2 no es un agregado prístino de materiales presolares.
- El cometa contiene una mezcla de materiales tanto del interior como del exterior del sistema solar.
- La evidencia sugiere que el material del sistema solar interno de alta temperatura fue transportado al Cinturón de Kuiper antes de la acreción de cometas.
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